RESISTANCE OFSACCHARUMSPP. AGAINSTCHILO SACCHARIPHAGUS INDICUS(KAPUR) (LEPIDOPTERA: CRAMBIDAE) IN INDIA

SUMMARYAccessions of fourSaccharumspp. from the world collection of sugarcane germplasm maintained at the ICAR-Sugarcane Breeding Institute Research Center, Kannur, Kerala State, India, were screened againstChilo sacchariphagus indicus(Kapur) (Lepidoptera: Crambidae), commonly known as internode borer. Observations on the progression of borer attack in the most susceptibleSaccharum officinarumindicated that the incidence began in the first fortnight of July, increased in the next 2 months and reached its peak in September. Thereafter, the incidence decreased in the next 2 months but reached its overall peak in December. Simple correlation coefficients between mean monthly weather parameters and borer incidence were not significant. Percent of canes attacked was significantly lower in 2011 than in 2012 forS. officinarum,Saccharum barberiandSaccharum sinensebut did not differ between the years forSaccharum robustum. Amongst the fourSaccharumspp.,S. robustumshowed the lowest borer incidence whereasS. officinarumrecorded the lowest attack intensity. Whilst infestation index showed the same trend as percent canes attacked, percent deadhearts did not differ amongst the fourSaccharumspp. Considering the 171 accessions evaluated, 29 (16.9%) accessions were resistant, 39 (22.8%) moderately resistant and 103 (60.2%) susceptible to internode borer. Out of the 39 accessions ofS. officinarum, none occupied the resistant category whereas 17.9% were in the moderately resistant category. InS. robustum, whilst nearly half (44.5%) the accessions emerged as resistant, a considerable number occupied the moderately resistant category. InS. barberi, no accession was resistant to the borer. InS. sinense, only one accession each represented resistant and moderately resistant categories. Plant morphological characters, yield and quality parameters did not show clear-cut relationship with the three infestation parameters.

Bio-intensive management of internode borer (Chilo sacchariphagus indicus Kapur) and stalk borer (Chilo auricilius Dudgeon)

parasitoid, Trichogramma chilonis, larval parasitiod, Cotesia flavipes and pupal parasitoid, Tetrastichus howardi against sugarcane internode and stalk borer in RBD with a plot size of 72sq.m. The incidence of internode borer ranged from 2.34 to 4.91% in treated plot as compared to control (7.87%) in August, however during October incidence ranged from 2.14 to 6.86%.At harvest, minimum incidence of internode borer (5.62%) was observed in T. chilonis followed by C. flavipes (7.52%) released plots. The released parasitoids are more active in the field for its parasitisation and multiplication which result a reduction in the incidence of INB in released plots where as beyond October the prevailing low temperature, appeared to be non-conductive for its mating and field parasitisation. The incidence of stalk borer during August and October was low (1.03- 5.54%). At harvest minimum incidence (5.55%) was observed in C. flavipes followed by T. howardi release plots (10.92%) as against 17.24% in control. Removal of dry leaves and late shoots was observed to reduce the damage by migratory borer larvae in August and October. The results indicates that parasitoids (egg, larva and pupal) play a significant role in the management of INB and SB to check the spread and lowering the incidence of this pests. It is suggested that a working of these parasitoids can be exploited in programmes for management of sugarcane stalk and internode borer.